I just want some additional security, privacy, and piece of mind. Would a simple script with iptables with dropping incoming connections be all that is required? What other options might I have?

you may want to check out guarddog or firestarter as GUI frontends to develop iptables structures..

personally... i really like SmoothWall. It is a customized Linux distrobution... so it needs to run on it's own box... it works great... i have been running one at home and in a corporateenvironment for a little over a year now.. not a single breach.. and the box doesn't have to be very powerful either... the one I use at home is a Pentium MMX 200 MHz with 32 MB RAM and a 3 GB HDD...

All configuration is done via web-interface...definitely worth checking out if you have a spare old box somewhere... I also have been wanting to check out m0n0wall and pfSense(both based on FreeBSD) which are firewall distro's with a web interface similar to SmoothWall.. I just haven't had time, and SmoothWall works great.... otherwise... like I said.. guard dog and firestarter are good GUI's to help with your iptables implementation...

ok, cool. So with Smooth wall, you can just do a default install on a machine plug in an ethernet cord and remote config; similar to a linksys router config? I am def gonna try firestarter, thanks.

yeah, except you need 2 network cards... 1 for the internet and 1 for the internal network... let me try to draw a rudimentary diagram...
I think you get the point...

anyways.. yeah.. it's an easy and fast install(the ISO is only a little over 30MB) and then some basic configuration in an ncurses based system for configuring your red and green connections(red=internet, green=local network).. setting up IP's, DHCP server(if you want it to do that), etc... It's really easy... and there is a help forum on the smoothwall site.. they are fast to respond and friendly... just as they are on this site...

good luck

Basically most firewalls just setup iptables for you, then add a few logging options. So if you are competent with iptables I would recommend just using that.
Personally I use Shorewall for my single computer setup, as using a seperate firewall box seems overkill for my needs